Re-designing front window in flexible CIGS modules for cost-effective moisture protection

Publieke samenvatting / Public summary

Flexible PV modules are attractive because of their low weight, freedom of form, and ease of integration. However, one third of the cost of present CIGS-based modules is dictated by the transparent frontsheet. This high cost is primarily due to the extreme moisture barrier properties required to protect the chemically unstable Al:ZnO (AZO) transparent contact.

Goal is to reduce the cost of the front sheet by 50%. By improvement of the stability of the electrical front contact layer of the CIGS, implicating less stringent requirements on moisture barrier properties, flexible and low weight front sheets for CIGS modules become economically feasible. Crucial for the Solliance and SEAC roadmap towards free form back end interconnected CIGS, is to increase the stability of the mass produced non-encapsulated CIGS stack during transport and storage before customization.

Korte omschrijving
TNO will develop, demonstrate and test the improvement of TCO stability by application of barrier layers by spatial ALD. Test devices, cells and modules will be made on the Solliance CIGS line. Based on technology assessment and cost calculations, Meyer Burger will implement selected processes for TCO and barrier deposition on tools, and demonstrate deposition on module level. Both AZO and intrinsically more stable TCO's will be studied. Foreign research partners in the ERANET project will focus on deposition of alternative TCO's by sputtering, perform module testing, and also explore frontsheet with self cleaning properties. Foreign industrial CIGS manufacturers will supply test modules, and form an industrial exploitation commission with Meyer Burger for commercial evaluation and implementation. TNO will assess the effect of improved TCO stability on storage time of prefabricated non-encapsulated CIGS.

The chemical stability of the front TCO on CIGS will be improved by exploring AZO and a number of intrinsically more stable alternatives in combination with low cost ALD barrier layers as part of the device. Feasibility of encapsulation with 50% lower cost front sheet will be demonstrated on sample modules of participating industrial manufacturers and utilizing innovative coating tools supplied by participating equipment manufacturer. Beneficial effect on storage time of semifinished products will be assessed.